For image-on-image (IOI) electrographic imaging, it is desirable and perhaps even necessary to have scavenge-less development subsystems that will not disturb existing images on the photoreceptor. In known systems, this is accomplished by using wire-based development systems such as Hybrid Scavenge-less Development (HSD), where one or more fine metallic wires (e.g., sliding on donor surfaces) are used to introduce toner into the development NIP as a powder cloud. This introduction of toner as a suspended cloud is referred to as fluidization. Unfortunately, the wires quickly become contaminated with particulate matter comprising unmodified and modified toner (e.g., crushed and pressured-fused toner sometimes known as “corn flakes”) and related flow and charge-control agents. This material is capable of trapping charge and modulating the local electric field near the surface of the wire. This uncontrolled charge introduces undesirable artifacts into the image developed on the photoreceptor. The typical solution to this problem is to frequently replace the wires. This leads to unacceptable downtime of the product, unsatisfied customers, high maintenance costs, and a significant loss of revenue.
Other methods of toner fluidization include DC and AC jumping and hybrid jumping development (HJD) All of these approaches, however, suffer from shortcomings that are manifested in developed image artifacts. A better approach is needed to fluidize the toner and develop images uniformly with a minimum of background.
A wireless method for toner fluidization to achieve 101 (image-on-image) development is also known and described in U.S. application Ser. No. 11/691,834, filed Mar. 27, 2007, and entitled “Systems and Methods for Momentum Controlled Scavengeless Jumping Development in Electrophotographic Marking Devices,” which application is incorporated herein by reference in its entirety. This previous method provides a technique to modulate the potential applied across the nip region in such a way as to allow development to occur on the photoreceptor, driven by the latent charge image, with undue scavenging action. In this technique, the period of the conventional jumping development cycle is divided into four stages to achieve the sequential effects of injection (dislodging the toner from the donor's surface and injecting it into the nip region), momentum control (decelerate the toner particles while they are still in flight), drift (allow low-speed toner particles to hang in space near the receiver), and reset (encouraging undeveloped toner in the cloud to migrate back towards the donor).